Casting machine with lightweight casting wheel



United States Patent [72] Inventors George E. Lenaeus, Carrollton, and

John H. Murphy, Atlanta, Georgia [21] Appl. No. 770,050 [22] Filed Oct.23,1968 [45] Patented Oct. 27, 1970 [73] Assignee Southwire CompanyCarrollton, Georgia a corporation of Georgia [54] CASTING MACHINE WITHLIGHTWEIGHT CASTING WHEEL 14 Claims, 7 Drawing Figs.

[52] U.S.Cl 164/278, 164/273 [51] Int. Cl B22d ll/06 [50] Field ofSearch 164/87, 273, 278, 283

[56] References Cited UNITED STATES PATENTS 3,321,007 5/1967 Coferet a].164/87 3,329,197 7/1967 Cofer 164/87 3,346,038 10/1967 Properzi 164/2783,411,565 11/1968 Properzi l64/283X 3,464,483 9/1969 Cofer et a1. .vl64/283X FOREIGN PATENTS 668,338 3/1952 Great Britain 164/87 PrimaryExaminer-J. Spencer Overholser Assistant Examiner-R. Spencer AnnearAttorney-Jones and Thomas ABSTRACT: The casting machine disclosed is acasting machine having a casting wheel which is generally U" shaped intransverse cross section, which is mounted on a casting machine by beinginserted into an annular channel between two mounting members thatengage only the sides of the casting wheel and only with edges that arerelatively narrow and that are displaced inwardly from the outer edgesof the casting wheel, and which has all of its portions sufficientlythin for the thermal stress in compression induced during casting in themetal from which the casting wheel is formed not to exceed the yieldpoint in compression ofthc metal.

Patented Oct. 27, 1970 3,536,126

Sheet 2 of 3 INVENTORB. George ELLenaeus BYJOhn liMuvphy A TTOR/Vi X5CASTING MACHINE WITH LIGHTWEIGHT CASTING WHEEL BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates to thecasting of metals and more particularly to a casting machine in whichmolten metal is cast in a casting mold formed by a peripheral groove ina rotating casting wheel and by a band which closes a length of thegroove.

2. Description of the Prior Art The casting of molten metal using acasting machine having a rotating casting wheel with a peripheral groovethat is closed by a band to form a casting mold is well-known in theart. Such a casting machine is shown in U.S. Pat. No. 3,279,000 issuedon Oct. 18, [966, to D. B. Cofer, et al., for an APPARATUS FORCONTINUOUS CASTING OF METAL, in U.S. Pat.

No. 3,318,369 issued on May 9, 1967, 116 to T. L. Bray, ct

al., for a COOLING SYSTEM FOR CASTING WHEEL", or in U.S. Pat. No.3,319,700 issued on May l6, I967 to T. L. Bray, et al., for a RADIALCOOLING SYSTEM FOR CASTING WHEEL.

A characteristic, of a prior art casting machine such as is shown by oneof these U.S. patents is that the casting wheel is a rather massivestructure which has generally been manufactured by forging andsubsequent machining on a large lathe. As a result, the casting wheel ina prior art casting machine of this type causes many problems in thecasting ofmolten metal.

For example, the fact that the casting wheel must be manufactured byforgingand subsequent machining makes the cost of manufacturing thecasting wheel relatively high and places a practical limitation on thediameter of the casting wheel even though it is known that a largediameter lessens the amount of straightening to which a cast bar issubjected as it leaves the casting wheel. Moreover. the weight of acasting wheel which is a rather massive structure makes the castingwheel difficult to mount upon and remove from a casting machine andgenerally makes it necessary to use special lifting equipment in orderto accomplish the mounting or removing of the casting wheel.

These problems with a casting wheel in regard to the cost ofmanufacturing and the mounting of the casting wheel upon or removing ofthe casting wheel from a casting machine are accentuated by stillanother problem with the casting wheel when the prior art castingmachine is used in the casting of a metal such as copper which is castat a relatively high tern perature. This is because the relatively hightemperature of the metal being cast in the casting whccl causes athermal stress in compression in the metal from which the casting wheelis formed that is greater than the yield point in compression of themetal. As a result, the surface of the peripheral groove in the castingwheel cracks and otherwise deteriorates so rapidly that the useful lifeof the casting wheel is generally less than ten hours. Thus, the castingwheel must be frequently replaced on a prior art casting machine and thecost of manufacturing the casting wheel and the difficulty with whichthe casting wheel is mounted upon and removed from the casting machinebecome even more significant factors in the cost of producing moltenmetal with the prior art casting machine.

The problem with the casting wheel of a prior art casting machinerelating to the cost of manufacturing the casting wheel can be partiallyalleviated by machining the casting wheel after it has been removed fromthe casting machine so as to repair the surface of the peripheralgroove. However, the peripheral groove of the casting wheel can berepaired by machining only a limited number of times before thestructural integrity of the casting wheel is lost by removal of metal orbefore the entire structure of the casting wheel is damaged by the heatof the molten metal. Moreover, each repairing ofa peripheral grooverequires that the casting wheel be removed from and mounted upon thecasting machine so that the problem with the casting wheel of a priorart casting machine relating to the difficulty with which the castingwheel is mounted upon and removed from the casting machine is notalleviated by repairing the peripheral groove. 7

An attempt to alleviate the problem with the casting wheel of a priorart casting machine relating to the difficulty with which the castingwheel is mounted upon and removed from a casting machine by providing aremovable liner to form the peripheral groove such as that linerdisclosed in U.S. Pat. No. 3,31 l,955 issued on Apr. 4, i967, to R.Richards for a DISPOSABLE MOLD MEMBER FOR CASTING MACHIN- E" has beenonly partially successful. This is because the liner is supported by asupport structure which must be relatively massive and which must bemanufactured by forging and machining in order to provide the recess inwhich the liner is positioned. Moreover, the liner and support structurerespond almost as a single unit with respect to the inducing of thermalstress by molten metal and as a result the liner deteriorates in use sorapidly that it must be frequently replaced on the casting machine. Inaddition, because molten metal in the liner must be cooled by colantapplied to the support structure or within channels provided by thesupport structure, both the liner and support structure must becarefully manufactured to insure that the liner fits snugly into therecess in the support structure so as to achieve the proper applicationof coolant to the liner.

Furthermore, a problem with the casting wheel ofa prior art castingmachine which is encountered with or without the use of a liner is thatthose portions of the casting wheel or support structure which definethe sides and bottom of the peripheral groove often have a thicknesswhich is determined in large part by consideration of the structurerequired to mount the casting wheel or the support structure rather thanby consideration of the most efficient cooling of molten metal in theperipheral groove. As a matter of fact. it is the usual thicknessofthcse portions of the casting wheel or the support structure of aprior art casting machine which causes the rapid deterioration of thesurface of the peripheral groove that is a significant problem with thecasting wheel and which contributes to the other problems consideredabove.

SUMMARY OF THE INVENTION The invention disclosed here overcomes theseand other problems associated with the casting wheel of a prior artcasting machine for the casting of molten metal in a peripheral groovein the casting wheel which is closed by a band. This is because theinvention provides a casting machine with a casting wheel which has arelatively low cost of manufacturing, which may be of substantially anydesired diameter, which is relatively light in weight and otherwiserelatively easy to mount upon and remove from a casting machine withoutthe use of special lifting equipment, and which has those portionsdefining the sides and bottom of the peripheral groove of a thicknessthat facilitates the cooling of molten metal in the peripheral grooveand that retards the deterioration of the surface of the peripheralgroove. These improvements in a casting machine are provided by acasting wheel which is generally U" shaped in transverse cross section,which is mounted on a casting machine by being inserted into the annularchannel between two mounting members that engage only the sides of thecasting wheel and only with edges that are relatively thin and displacedinwardly from the outer edges of the casting wheel, and which has mostor all of its portions relatively thin.

Since the casting wheel in the casting machine provided by the inventionis substantially a ring which is generally U" shaped in transverse crosssection and which requires that no portion be of excessive thickness, acasting wheel having substantially any desired diameter is convenientlymanufactured from a metal such as low carbon steel by forming a ringfrom sheet stock, a channel or the like in a conventional ring formingmachine and by welding the abutting ends of the ring together. Moreover,since the casting wheel is mounted on a casting machine by beinginserted into an annular channel peripheral groove; V

to be engaged by a flexible metal band, theeasting wheel need I:

not be manufactured as a substantially perfect circle.

' It is because of these manufacturing circumstances that the 5 gcasting wheel in the casting machineprovided by theiinven-I tion has arelativelylow. cost of manufacturing and maybe of substantially;.anydesireddiame'tei-L It is because of the relativelylight weight oftheresulting structure and the mounting of the casting wheel byinserting the castingwheel into an anl nular channel that thecastingwheel is relatively easy to mount i I Y 7 I i i i seen from FIG.l that a casting wheel 10 in an embodiment of upon andremove fromacastingmachine.

The mounting of the casting wheel by inserting the casting- "wheelintoan annular channel between the edges of two mounting members provides acastingwheel in which those which facilitates cooling of molten metal inthe peripheral groove by coolantsprayed on the casting wheel or in achannel defined by the casting wheelanda partition positioned betweenthe mounting members inwardly of the casting wheel.

ll is'be'eause no substantial portion of the easting wheel is of athickness that results in molten metal ,in' the casting wheel causing athermalstressin compression in excess of the yield point inycompressionof themetal from which the casting wheel is formed that the thicknessofthose portions of the, 30 casting wheel which define theperiphcralgroove is such'as tok retard the deterioration of the surface of theperipheral groove encountered in the prior art. I

BRIEF DESCRIPTION OF THE DRAW-1N0? a 35 These and other features andadvantages of the invention will 'be more clearly understood from thefollowing detailed description and the accompanying. drawing in whichlike characters of reference designatecorresponding parts '4 throughoutand in which:

H6. 1 is a cross-sectional-vie w through a casting wheel I showin'gafirst embodiment of the invention disclosed herein;

FIG. 2 is a cross-sectional view through a casting wheel showing asecond'embodiment of the invention disclosed' '4-g herein; 7 I a i g 7FIG. 3 is aphotomicrograph showing a prior art casting wheel at andadjacent the surface of itsperipheral groove following approximatelythree and one-half hours of casting; and

FIG; 4 isa photomic rograph showing the castingwheelof FIG. 1 at andadjacent the surface of its peripheral groove fol- I lowingapproximately three and one-halfhours of casting; J l

-F1G. 5 is'a graph showing the thermal stressin themetal of 1 thecastingwheel ofra priorart casting machine, the casting wheel beingformed of 510W carbon steeland thermal stress being a function of timefollowing'the pouring of molten copper into the peripheral groove;

F1656 is a graph showing the thermal stress in the metal'of the castingwheel of a prior art casting machine, the casting wheel being formed ofcopper and thermal stress being a func-. tion of time following thepouring of molten copper intothe 'FIG. 7 is a graph showing th'ethermalstress in the metal of the casting wheel-of alcasting machineembodying the'invention disclosed herein, the casting wheel being formedof low 7 carbon steel and thermal stress being a function of timefollowing the pouringflof molten c'o ppe r into the I. peripheralgroove.

DESCRIPTION 0? EMBODIMENTS These l-los. and the following detaileddescription disclose specific embodiments of the invention. However, itwill be understood that the invention may be. embodied in otherequivalent forms without departing from the inventive concept.

' i As indicated above, the invention disclosed herein is a castingmachine having a castingwheel 10 'which avoids many problems encounteredin the prior art. Apart from thecasting wheel 10, the casting machine issubstantially as shown by one of the patents listed above in; describingthe prior art. Accordingly, only the castin g'wheellfl and relatedmounting structure are shown in the drawing and described below sincethe use of the casting wheel 10 on a casting machine and thosestructural components of a casting machine not shown or described willbe understood by those skilled inithe art.

Considering thecasting wheel .10 shown in FIG. 1, it will be theinvention disclosedherein is a continuous ring having a casting wheelllldefinesa peripheral groove 11 by opposed walls 12 and 13 and'by abottom 14. The walls 12 and 13 and bottom 14 cooperate with abandM15'positioned againsty the casting wheel '10-in conventional nanner to forma casting moldM. l I

.ltwill be seen from l'that thegeasting wheel 10 is of substantiallyuniform thicknessfin' transverse cross section so that the walls 12 andl3"-an d. the. bottom 14 defining the peripheral groove '11 areofrsubstantially equal thickness. In

addition; it will be seen that the walls 12 and 13 and the bottom 14 areof substantially the same thickness as the band 15. 'lhecasting wheel 10is mounted on'a casting machine by being inserted into an annularchannel 16 provided by a mounting means including an inner mountingmember 17 and an; outer mounting member.18:"Theinner mounting member 17'includes an inner angle member 19 which is attached by a.

plurality of bolts such as bolt 20 to an inner ring member'2l. The innerring member 21 isin turn attached by a plurality of bolts such as bolt22to eircular mounting plate 23. It will be understood that the circularmounting plate 23 is mounted on a suitable shaft (not shown) forrotation during the casting of molten metal in conventional manner. l v

The outer mounting member 18' includes an outer angle membcr24 which isattached by a plurality of bolts such as bolt 50 to an outer ring member.25.1 The outer ring member 25 ispositionedlaterally relative to thc3inner ring member 21 by a plurality of positioning members sup aspositioning member "26ywhich are. positioned aroundthieficircumference-of-the inner ring member 21"and e'xtend ibetween theinner, ring member 21 and outer ring inember' -ZiEEach positioningmember 26is a shaft127 ex tending through an aperture 51 in the innerring member 21' and'a' n aperture 29 inthe outer ring member25; X v H 7That end of the shaft 27 extending through the aperture 51 in the'innerring member 21jis threaded to receive an inner nut 28 and an outer nut29 which serve toattach the shaft 27 to the inner ring member2l byengaging oppositesides of the inner ring member 21, Similarly, that endof the shaft 27 extending throughthe aperture 29in the outer'ringmember25 is threaded to receiveja n in'iier. nut 30 and an outer nut 31 whichserve to attach the shaft 27. tothe outer ring member 25 by engagingopposite sides ofthe outer ringmember 25, it will be understood-thatpositions of the nuts 28, 29,

i 30, and 31 on the shaft 27 p5mpnthe lnni ring member 2l relative tothe outer ring member-25. Moreover, it will be unthe outer ring member25,}the casting wheel 10 is firmly wedged into the annular channel 16 ormay simply ffioat in i l the annular channel 16 Hgw everfif 'the castingwheel 10 is I wedged into the annular channel l6,"that portion 32 of theinner angle member .19 which engages the casting wheel 10 is relativelythin and engage s the wall 12 of the casting wheel 10 only in a circlethat row gin width relative to the radial width of the wall 12 and thatis displaced inwardly from the outer edge 33 of the wall [2. Similarly,that portion 34 of the outer angle member 24 which engages the wall 13of the casting wheel is relatively thin and engages the wall 13 of thecasting wheel 10 in a circle that is narrow relative to the radial widthof the wall 13 and that is displaced inwardly from the outer edge 35ofthe wall 13.

In that embodiment of the invention shown in FIG. 2. the casting wheel10' is also a continuous ring member having a transverse cross sectiongenerally resembling the letter However, in that embodiment of theinvention shown in FIG. 2, the casting wheel 10' is not of uniformthickness in transverse cross section and as a result, the walls 12 and13 adjacent the bottom 14' are of greater thickness than the walls 12'and 13 at the outer edges 33 and 35' Moreover, in the casting wheel 10'shown in FlG. 2. the inner ring member 21' and the outer ring member arepositioned relative to each other by a plurality of spacing members suchas the spacing member 36 which is similar to a positioning member 26 inthat embodiment of the invention shown in FIG. I except that a spacingmember 36 does not include outer nuts 29 and 31. The outer sufaces 37and 38 of the walls 12' and 13' are substantially perpendicular to thebottom 14' so that the walls 12' and 13' must be welded to the anglemembers 19' and 24 or a plurality of brackets, such as bracket 42 shownin dashed line in FIG. 2. must be mounted on the inner ring member 2l'in order to position the casting wheel 10' in the annular channel 16'.When the casting wheel 10' is welded to the angle members 19 and 24',spacing members such as the spacing member 36 are used simply tomaintain the lateral spacing between the ring members 21 and 25'.However, it will be understood that positioning members such as apositioning member 26 can be used with the casting wheel 10" and thatthe casting wheel 10 shown in FlG. 1 can be welded to the angle members19 and 24 so as to increase the rigidity of the casting wheel 10.Moreover, it will be understood that even though the casting wheel l0 iswelded to the angle members 19 and 24'. the portions 32' and 34' ofthCangle members 19' and 24' engaging the casting wheel 10' are relativelythin and engage the casting wheel 10 in circles that are relativelynarrow and that are displaced inwardly fromthe outer edges 33 and 35ofthe walls 12' and 13'.

From the foregoing description of two embodiments ofthe inventiondisclosed herein, it will now be understood that a casting wheel 10 or10' in a casting machine embodying the invention is a continuous ringhaving a transverse cross section generally resembling the letter U" andwhich is mounted on a casting machine by being inserted in an annularchannel l6 or 16' between two mounting members 17 and 18 or 17' and'l8'so that it is engaged by only relatively thin portions 32 and 34 or 32'and 34' in circles that are relatively narrow and that are displacedinwardly from the outer edges 33 and 35 or 33' and 35 of the castingwheel 10 or 10. The casting wheel 10 of substantially uniform thicknessin transverse cross section shown in FIG. 1 is conveniently manufacturedfrom sheet stock of low carbon steel having a thickness of approximately.12 inches by using a conventional ring forming machine to form a ringand by welding the abutting ,ends of the ring together. Similarly, thecasting wheel 10 of varying thickness in transverse cross section shownin FIG. 2 is conveniently manufactured from a conventional three inchship building channel oflow carbon steel by using a conventional ringforming machine to form a ring and by welding the abutting ends of thering together.

Thus, a casting wheel 10 or 10' has a relatively low cost ofmanufacturing and may be of substantially any desired diameter becauseof the method by which it may be manufactured. Moreover, since a castingwheel 10 or 10' is simply inserted into an annular channel 16 or 16 andsince only the outer edges 33 and 35 or 33 and 35' are engaged by a band15, a casting wheel 10 or 10 need not be a perfect circle and thisreduces the cost of manufacturing regardless of method of manufacture.

it will be understood that in a casting wheel 10 manufactured from sheetstock having a thickness of approximately .12 inches, the walls 12 and13 and bottom 14 have a thickness of approximately .12 inches.Similarly, it will be understood that in a casting wheel 10 manufacturedfrom a three inch ship building channel, the walls 12' and 13 vary inthickness from .25 inches to .5 inches and the bottom 14' has athickness of approximately .25 inches.

Thus, regardless of the material used in the casting wheel 10 or 10' orthe diameter ofthe casting wheel 10 or 10, a casting wheel 10 or I0 isrelatively light in weight compared to the casting wheels of prior artcasting machines which have rather massive structures. Moreover, it willbe understood that because of this relatively light weight and becausethe casting wheel 10 or 10' is mounted on casting machine simply bybeing inserted into a channel 16 or 16, a casting wheel 10 or 10' isrelatively easy to mount upon and remove from a casting machine.

In connection with mounting a casting wheel 10 or 10' on a castingmachine or removing a casting wheel 10 or 10 from a casting machine, itwill be further understood that a casting wheel 10 or 10' can beinserted into or removed from a channel l6 or 16' with the angle membersl9 and 24 or 19' and 24' being mounted on the casting machine or withthe angle members l9 and 24 or 19' and 24 being welded to the castingwheel 10 or 10' so that they are mounted on and removed front thecasting machine with the casting wheel 10 or 10. However, even thoughthe angle members 19 and 24 or I9 and 24 are welded to the casting wheel10 or 10, the casting wheel N) or 10' is still relatively light and canbe mounted upon and removed from a casting machine without the use ofspecial lifting equipment.

The absence in a casting wheel 10 or l0 of any portion of excessivethickness not only makes the casting wheel 10 or 10' relatively lightbut also serves to pro\ ide a casting wheel 10 or 10' which facilitatesthe cooling ol molten metal in the peripheral groove II or ll. Foreutmple. in the casting wheel 10 shown in FIG. 1. the walls 12 and I3and the bottom 14 may be of substantially the same thickness andmaterial as the band l5 so that cooling around the transverse crosssection of molten metal in the peripheral groove ll is substantiallyuniform. However, in the casting wheel 10' shown in FIG. 2. the walls 12and 13' vary in thickness so that cooling is related to the mass ofmolten metal in the peripheral groove ll adjacent each portion ofa wall[2' and [3.

Thus, the walls 12 and [3 or l2 and 13' and bottom 14 or 14' may besubstantially of any desired thickness to provide for a desired transferof heat from molten metal in the peripheral groove ll or H to coolant.In this connection. it will be understood that coolant may be sprayed onthe casting wheel 10 or 10' as in the casting machine shown in U.S. Pat.No. 3,279,000 referenced above or may be in a channel 40 such as oneformed by a partition 41 between ring members 21' or 25' and which issimilar to the channels used in the casting machine shown in U.S. Pat.No. 3,318,369 referenced above.

In addition to facilitating the cooling of molten metal in a peripheralgroove 11 or II, relatively thin walls 12 and 13 or 12' and 13 andbottom 14 or 14' in a casting wheel 10 or 10' of a casting machineembodying the invention disclosed herein serve to provide a castingwheel 10 or 10' having a useful life which is longer than that ofcasting wheels used in prior art casting machines. This is because therelatively thin walls 12 and 1 3 or 12 and I3 and bottom 14 or 14'retard the deterioration of the surfaces of the walls 12 and 13 or 12'and 13 and the bottom 14 or 14 defining the peripheral groove ll or 11'as is shown by a comparison of HG. 3 with FIG. 4.

F IG. 3 is a photomicrograph of a casting wheel in a prior art castingmachine such as that shown in U.S. Pat. No. 3,318,369 showing thesurface 43 of the bottom 44 that defines in part the peripheral groove45 of the casting wheel. The surface 43 is shown as it appears afterapproximately three and one-half hours of use. FIG. 4 is aphotomicrograph of the surface 47 of V manner indicated in FIG. 4.

the bottom l4 that with the walls 12 and I3 defines the t peripheralgroove of a casting wheel 10. The surface also shown as it appearsafterapproximatelythree and onehalf hours of use. The ca'sting wheel shown inFIG. B and the castingvvheel 10 shown in FIG. 4 were both formed of lowcarbon steel and the bottom 44 was approximately .5 inches thick. whilethe bottom l4 was-only approximatelyl2 inches thick v of the wallslZ andI3 or I2 and IS' and of the 14 or 14' is less than thatc'riticalthickness at whichth J stress induced by molten metal in a peripheralgroolie II or 11' exceedsthe yield 'point in compressionofthe -nietalfrom which 'thereasting wheel'ltl or 10' is formed. For each particularmetal from which. a casting wheel 10 or l" is formed, the

1. yield point in,compression and thiscritical thickness dependComparing F IG. 3 and FIG. 4. it will be seen that'the surface 43in thecasting wheel of the prior art casting machinelhas deteriorated whilethe surface'47in the casting wheel 10 is in substantially bettercondition.

The'reason that the relatively thin walls 12 and 13 or I2 I and I3"andthe relatively thin bottom 14 or 14' retard det'cri oration in acasting wheel 10 orIO' of a surface such as the surface 47 in FIG. -4isshown'by FIGSQS. 6. and7. Fig. 5 is a graph "showing in pounds persquare inch the thermal stress incompression at a surface such as thesurface 43 of the bottom 44 of the casting wheel of a prior art'castingmachine shown in FIG. 3. The casting wheel was formed of low carbonsteel and the thermal stress shown in FIG. 5 is a function of time inseconds following the pouring of molten copper into" a peripheral groovesuch as the peripheral groove 45 shown in FIG.3.'-' I no. 6 is similarto FIG. 5 except that it is for the casting wheel of a prior art castingmachineinwhich the casting wheel is formed of copper rather than of lowcarbon steel, However,

upon the operating conditions of the casting wheel suchas cooling andother factors and can be readily determined by one skilled in the art..lnthis connectiongit will be understood that the thermal stress incompressionis proportional to the thickness of a wall 12,113,112 or. I3or bottom 140? 14' and j t that even for a casting wheel or 10'. :formedof low carbon steel. thethicknessof thc wallsl2 andtl3 or: 12 and-I3.and of the'bottoml4 or l4 may generallybe greater than' theapproximately .12 inches of the bottom. 14 for which FIG. T

I shows thermal stress andthat certain portions of the wall I2 and 13'mayunder some loperatingcon ditions be relatively thick such as in thecasting machineuIO' without excessive deterioration of theperipheralgroovel If occurring.

. In connection with the significance of the particular metal from whichthe casting wheel I0 or-IO. is formed. it is to be noted from FIG. 6that althoughthetthermal stress in the copper from whichthe castingwheel is formed is less than 30,000 pounds per squareinch, it isnevertheless in excess of I8',000 pounds per square inch which can beregarded as the FIG. 7 is for a casting wheel 10 formed oflow carbonsteel and used' in an embodiment of the invention disclosed herein inthat the walls 12 and 13 and the bottom I4 are sufficiently thinto-retard deterioration such as that shown by FIG. 3' in theAlthoughFlG. 7shows in pounds per squarcinch thermal stress incompression at a surface such as thcsurfaceflof the bottom 14 in FIG. 4of a casting wheel 10 which is formed of .low. carbon steel,FIG.f7'is'reprcsentative of any casting wheel 10 or 10' in anembodimentof the invention disclosed herein. In'this connection shouldbe understood that the bottom I4. for which FIG. 7 shows thermalstress'is only approximately .1 2 inches in thickness while the bottom44 for e which FIGS. 5 and 6 show thermal stress is approximately .5

inches in thickness. H e

, Upon examining FIGS. 5, 6,.and 7 it is seen that'shortly after 1molten m etal is received in a peripheral groove '11 or 45. the.

thermal stress reaches a maximum value. From FIG. 5 it is 1 the walls 12and I3 or I2 and I3. and the bottom 14 or 14' seen that when the bottom44. is of low carbon steel and has a sion is substantially'less than30,000 pounds per square inch.

Those skilled in'theartwill understand that the yield point incompression for low carbon steel can be considered to be approximately30,000 pounds per squareinch underccrtain operating conditions of acasting wheel-Thus, inthe casting.

wheel of aprior'art casting machine such as that represented byFIG. 5.the thermal stress incompression inducedin the metal of the castingwheel by molten metal exceeds'the yield.

point in compression of lowcarbon 'steel. while in casting thickness ofapproximately .5 inches, the maximum value of the thermal stress incompression is well in excessof 30.000 pounds per square inch. From FIG.7 it isisen that when the bottom 14 is also of low carbon steel but hasathickness of 'only approximately .12 inches. the thermal stress incompres yield point in compression of copper: under most operatingconditions of a casting wheel. However. even when a casting wheel- I0 or10 is formed of copper there is a critical thickness of the walls I2 and13 or 12' and I3 and of the bottom I4 or I4 at which thermal stress incompression does not exceed the yield point in compressionL-A.castingwheel I0 or 10' used under the same conditions as the casting .wheelrepresented by FIG. 6 and having walls 12 and I3 or I2' and I3 and abottom I4 or I4 will provide an embodiment of the invention disclosedherein if the walls I2 and I3 or 12' and I3" and the bottom I4 or 14'are approximately .30 inches in thickness rather than .50 inches inthickncss as in the casting wheel formed of copper represented by FIG-6.This is because are suflicicntly thin to retard the deterioration. bythermal stress of those surfaces defining a peripheral groove II or I I.

I In connection-with retarding thedeterioration of those surfacesdefining a peripheral groove II or .II'. it should be emphasized that in.th'ecasting of molten copper. a casting wheel 10 or I0 of low carbonsteel embodying the invention has been found to have a useful lifewithout removal from the casting mechine which isapproximately twicethat of a prior t art'casting wheel of low carbon steel. Thus. theadvantages of a casting wheel I0. or' I0 as to cost of manufacturing andrelative ease of mounting upon or removal frorna casting machine areaccentuated by a relatively long useful life.

It will be obvious to those skilled in the art thatmany variations maybe made in the embodiments chosen for the purpose of illustrating thepr'esent invention without departing from the scope thereof as definedby the appended claims. t 7

We claim:" h it y I. Ina-casting machine for casting a molten metal in aperipheral groove. a casting wheel having a portion which is formed of asolid metal and ,which on one sidedefiiles a surwheel 10 or 10' from anembodiment .of the invention disclosed herein such as that representedby'FIG. 7,.thefthermal stress in compression is'less than .theyieldpointincompression of low carbon steel. As is illustratedtby the line onthe,

graph ofFIG, 5, the yielded metal does not return to the zero embodimentof the invention disclosed hereimthe thickness face of said peripheralgroove and on another side defines an external surface for theapplication of a coolant, said portion having a thickness between saidone side and said another side which is less than that thickness atwhichthe thermal stress in compression induced in said solid metalbyheat from a molten metal in said peripheral groove equals the yieldpoint in comis copper.

pression of said solid metal.

2.1 The casting machine of claimjl in which said solid metal "is lowcarbon steel.

3. The casting machine of claim 4. The casting machine of claim Iin'which said casting wheel has a transverse cross section which issubstantially U" shaped. e l

1 hi which said solid metal 5. The casting machine of claim 4 includinga mounting means for forming an annular channel into which said castingwheel is placed for rotation.

6. The casting machine of claim 5 in which said mounting means includesa first mounting member and a second mounting member and in which saidannular channel is defined between an edge of said first mounting memberand an edge of said second mounting member.

7. The casting machine of claim 6 in which said casting wheel is engagedonly by said edge of said first mounting member and by said edge of saidsecond mounting member.

8. The casting machine of claim 6 in which said edge of said firstmounting member engages a radially extending wall of said casting wheelin a circle which is narrow relative to the radial width of said walland which is displaced inwardly from the outermost edge of said wall.

9. The casting machine of claim 6 in which said casting wheel is wedgedinto said annular channel.

10. The casting machine of claim 6 in which said casting wheel is weldedto said edge of said first mounting member and said edge of said secondmounting member.

11. The casting machine of claim 6 including a partition extendingbetween said first mounting member and said second mounting memberinwardly of said casting wheel and positioned to define a coolantchannel with said casting wheel.

12. The casting machine of claim 4 in which all portions of said castingwheel are of substantially the same thickness in said transverse crosssection.

13. The casting machine of claim 4 in which portions of said castingwheel are of varying thickness in said transverse cross section.

'14. The casting machine of claim 4 in which no portion of said castingwheel has a thickness greater than .5 inches in said transverse crosssection.

